Switched reluctance motors (SRMs) are doubly salient machines; that is, they have multiple poles on both the stator and the rotor. Moreover, there are coil windings on the stator, but no windings or magnets on the rotor. In a SRM, each motor phase comprises at least one pair of diametrically opposite stator poles, each stator pole having a coil winding wound thereon. The stator pole coil windings comprising each motor phase winding are connected in series or in parallel, so that when a phase winding is excited, magnetic flux produced in the corresponding pair(s) of stator poles combines additively. Upon excitation of a motor phase by supplying current to the corresponding stator pole coil windings, a magnetic force of attraction results between the excited stator pole pair(s) and the nearest rotor poles, thereby causing the rotor to rotate. Current is switched off in the excited motor phase winding before the rotor poles rotate past the aligned position; otherwise, the magnetic force of attraction would produce a negative or braking torque. Continuous rotation of the rotor is achieved by sequentially switching on and off adjacent motor phases. To excite the motor phases, undirectional current pulses synchronized with rotor movement are supplied to the motor phase windings by a converter. Exemplary SRM converters are illustrated in commonly assigned U.S. Pat. No. 4,684,867, issued to T. J. E. Miller on Aug. 4, 1987.
In general, during manufacture of a switched reluctance motor, the coil windings are wound as subassemblies and then applied to the stator poles because, as is well-known by those skilled in the art, the stator poles of a SRM are integral parts of the stator, i.e. are not removable, in contrast to, for example, stator poles of dc commutator-type machines. Disadvantageously, this conventional stator assembly process necessarily leaves unused spaced in each interpole region. That is, in order for a coil being assembled onto a stator pole to be able to clear adjacent windings that have been assembled previously, the width of the coil is restricted. As a result, for a particular SRM, maximum attainable flux, and hence output torque and voltage, are limited.